The present invention relates to illumination systems for motor vehicles, these systems providing an improved illumination beam in order to illuminate regions of the road where the vehicle is travelling other than those which are located along the longitudinal axis of the vehicle, in order to fulfil, for example, a cornering function.
A cornering function makes it possible to illuminate, when a vehicle is moving over a non-rectilinear trajectory, the portions of the road which are intended to be approached by the vehicle, which are to the front and at the side thereof, and which consequently are not illuminated or are badly illuminated by the conventional dipped or full-beam headlights.
In order to emit a light beam of this sort, it is known to provide the cornering function by altering the orientation of the headlight beam. A solution of this sort is not applicable to a dipped beam of the European code type, in which the rotation of the beam would risk leading to loss of adjustment in the photometry of the beam, which would then become incompatible with the regulations currently in force. Furthermore, from the perspective of the next change in the regulations permitting the rotation of the dipped beam, it will not then be desirable to rotate the main headlight by too great an amplitude, because of the total size of this headlight.
One solution therefore resides in altering the orientation of the beam of an additional headlight. Various means have already been proposed in order to obtain this result, which all involve optical components which can be moved in rotation and/or in rotation, when it is not the complete headlight which is rotated. This results in mechanical complication of the headlight and of its movement-control members, which is detrimental to the reliability of the system thus designed, and which substantially increases the cost of a cornering headlight of this sort.
Another known solution consists in placing, on the vehicle, a fixed headlight, the optical axis of which makes a larger or smaller angle with the longitudinal axis of the vehicle, the right headlight being oriented towards the right of the vehicle and the left headlight towards the left. The cornering beam is then obtained by the gradual or immediate switching-on of the headlight located on the side to which the vehicle turns. This solution makes it necessary to have an additional pair of headlights available on the vehicle, hence a large size of the illumination system of the vehicle.
The present invention is looked at in this context and its aim is to provide an illuminating headlight for a motor vehicle which is able to illuminate regions located outside the longitudinal axis of the vehicle, while complying with the photometry of dipped and full beams, without requiring an additional headlight dedicated to this illumination, and without requiring a movable part.
The object of the present invention is therefore a headlight for a motor vehicle, comprising a first reflector of elliptical shape, at a first focus of which is located a main light source, the light rays emitted by this source and reflected by the elliptical reflector being directed towards a concentration spot located at a second focus of the elliptical reflector, the first and second focuses of the elliptical reflector defining a main optical axis of the elliptical reflector, a convergent lens being placed such that its optical axis is coincident with the main optical axis of the elliptical reflector and that the second focus of the reflector is located on the focal line of the lens in order to emit a light beam of rays parallel to the main optical axis.
According to the present invention, the headlight comprises at least one optical system concentrating the light rays emitted by a second light source in the direction of a second optical axis passing through the optical centre of the lens and over a second concentration spot located on the focal line of the lens, and the first and second optical axes form an angle of between 20 et 45xc2x0 between them.
According to other advantageous and non-limiting characteristics of the invention:
the optical system comprises a paraboloidal reflector combined with an objective lens focusing the light rays emitted by the second light source and reflected by the second reflector onto the second concentration spot;
the optical system comprises a second elliptical reflector, the second light source being placed on a first focus of the second reflector, the second focus of the second reflector being located on the focal line of the lens, the focuses of the second reflector being aligned on the second optical axis;
the first reflector consists of two half-ellipsoids having the same focuses and different eccentricities;
the half-ellipsoid closest to the second reflector has an eccentricity greater than that of the half-ellipsoid furthest away from the second reflector;
a mask is placed on the main optical axis in the immediate vicinity of the focal line of the lens in order to delimit a cut-off in the beam of light rays coming from the main light source;
a mask is placed on the second optical axis in the immediate vicinity of the focal line of the lens in order to delimit a cut-off in the beam of light rays parallel to the second optical axis.